Fundamentals of Computer

Computer is a data processing machine which is derived from human intelligence, for processing it has to perform the following task:

Accept data from user (Input) Accept instructions from user (Input) Convert data into instruction (Processing) Display the result (Output)

What is Computer

Input processing outputData

Instructions Output

information

Garbage In Garbage Out

GIGO

Fast in processing, storage and retrieval

Large storage space Accurate Versatile Works automatically Diligent Compactness

Characteristics/limitations of computers

No intelligence No decision power Cannot learn with

experience

Characteristics Limitations

Digital Computer: Accepts digits and alphabets, works upon discrete data (0,1) Ex: Mini, micro, mainframe and super computers used business purpose

Analog Computers: Using signals as input, Operate by measuring rather then counting mostly used in scientific or engineering application Ex: thermometer, speedometer, voltmeter, Complex scientific calculation

Hybrid Computers: Use signals and digits as input, special purpose computers Ex: Used in hospitals to know the radio activity level & ICU used in mines, chemical processing.

Classification of computer

Block Diagram of Computer

Input

Control unit

ALU

Memory

Output

Central Processing Unit

CPU: Brain of computer to control all inputs Process the instructions, perform arithmetic and logical operations, data flow with in the computer, communicate with input and out units ALU: Electronic circuit, Arithmetic operations like +,-,*,%,

CU: Electronic circuit, to control the activities of the computer

Memory: active part to store, process and deliver the data when required

Central Processing Unit

2 types : primary memory Secondary memory

Primary memory 2 types 1. random access memory 2. read only memory Read only memory (ROM): data resides permanently, non

volatile, stores the program which is required to run the computer EX: Operating system, boot strap loader

Random access memory (RAM): data required by the program is stored in RAM, temporary memory, volatile, random access, also called as read/write only memory,

Expensive memory

Memory

Secondary memory:

called as external memory or main memory, high speed, Low cost, cost per bit is low,Ex: magnetic disk, magnetic tape, floppy disk, hard disk, CD

ROM, zip disk, Winchester disk, optical disk.

Memory

Smallest unit: bit 0,1

1 byte=8 bits 1024 bits=1 kilo byte 1024 bytes=1 mega byte 1024 megabyte=1gigabyte 1024 gigabyte=1 terra byte

Unit of Memory

Input: the process of entering and transforming data into machine readable form so that it can be processed by the computer.

Keyboard Joy stick Mouse MICR (Magnetic ink character recognition) OCR (Optical character reader) OBR (Optical bar code reader) Web camera Scanner

Input units

Out put devices: Electromechanical devices, accept data from computer and transfer into output device.

Monitors Printers Plotters Screen image projectors Voice response system.

Output Devices